Composition for dull raised printing



UNITED STATES i i I 2,226,867

COMPOSITION roa DULLI aarssnjrnmmd Patented Dec. 31, 1940 PATIENT ToFFica II Samuel Lipsius, New York, N.

6 Claims.

This invention relates to the printing of raised characters in simulation of the raised effects pro.-

.duced by the actionof dies or engraved plates and ordinarily known as embossing work or thermography or raised printing, and is an improvement over my Letters Patent Nos. 1,146,182. and 1,928,668. An objection to most compounds for and the processes of producing thermography or raised printing heretofore known and used is that the raised letters produced are glossy which is not desired for certain kinds of Work.

Applicant is aware that attemptshave been made to overcome this glossy effect by using a shellac ground and graded very fine and applying less heat than is required for gloss efiects. Such known attempts have not been entirely satisfactory however. Such a fine compound has quite limited raising qualities and the eifect produced is therefore only'a very slight raise. Again, on account of applying only a minimum of heat, only. a partial fusion takes place which results in a finished product that is ragged in appearance, feels sandy to the touch andis readily smudged and rubbed off the paper. 'In such attempts extra care also must be taken in fusing asthe slightest amount of excess heat fuses the powder particles lying nearest to the surface a trifle more than the others and produces a shine or gloss which is objectionable.

An object of the present invention is to retard gloss in raised printing, thermography, etc.

Another object is to provide a compound that will produce raised printing with dull, raised, rounded-out letters.

A further object is to provide an improved process for manufacturing a compound that will produce dull, raised, rounded-out letters.

A still further object is to provide raised printing, etc. that is dull in effect, with rounded, smooth letters.

The invention contemplates the bonding of resins, gum, shellac, or the like, with a chemical, which, with fusion of the resin or gum, etc. on the ink in the production of raised printing will so blend or become effective therewith as to give to the final product raised, dull, rounded-out letters to any degree desired and not dependent on heat.

After considerable experimentation it has been discovered that any suitable embossing compound such as shellac, gum elemi, gum sandarac, kauri, or the Rezyl resin, which is an alkyd resin modified with non-drying fatty acids, and a heavy metal soap such as zinc stearate or aluminum palmitate may be mixed together. in approximately the proportions of 16 parts by weight of the resinous material to 1 part by weight of the heavy metal soap.

The resinous material is in the usualform and the heavy metal soap added should be preferably more finely divided or finely enough divided to coat. the particles of the resinous material. When fused the raised letters formed in thermographic printing'ar'e found to be dull and free from gloss, the freedom from .fgloss'not being dependent on the particular degree of heat. The gloss retarding agent or heavy .metal soap appears to float on the top of the resinous base when melted, so that after the base hardens a roughened and non-reflecting surface for light is provided. The particles of the gloss retarding agent appear to float, probably due to the high surface tension of the resinous base material and to the reluctance of the particles of gloss retarding material to become wetted by themolten base so that the floating is not due so much to specific gravity as it is to tendency of the particles of gloss retarding material notto become wetted and the" high surface tension of the resinous base.

It has also beenfound that finely powdered magnesia may be: used as a gloss retarding agent for mixing with the resinous base and in the proportions previously mentioned. Applicant believes that any satisfactory material for thermographic printing may be used and it is believed the materials adapted for such use are characterized by their high surface tension when melted, in order to give the raised printing effect. The preferred base material is shellac and the preferred gloss retarding agent is zinc stearate. Any finely divided particles of a material which does not readily reflect light and the surface characteristics of which possess-difficulty in becoming wetted by the molten base of high surface tension, so that the particles appear to float, should, it is thought, be satisfactory.

For example, I take a good quality of resin, gum, shellac or the like, ground and graded to the desired mesh. With each pound of the meshed material there is thoroughly mixed approximately lb. of a substance such as zinc stearate. These materials are then incorporated and worked together as by being lightly rubbed by hand or by mechanical means so as to cause the fine particles of zinc stearate to more or less completely coat the grains of the material.

In the preferred method of bonding or binding the zinc stearate to the resin, gum or shellac or thte like, heat is used as the partially dissolving agen Among practical methods for binding these materials, a vibrating machine, such as is used for grading powders may be employed, with a closed bottom tray substituted in place of the vibrating screen and subjected to gas or electric heat distributed uniformly, preferably from underneath. As an instance, in a tray of approximately 25" x 25" exposed heating surface, a ten pound mixture of the meshed material and zinc stearate is vibrated for about one minute to insure substantially uniform admixture of same with the zinc stearate. Then a partially fusing heat is turned on for approximately 5 to minutes depending on the fusion point of the resin or gum used, or until proper amalgamation has been accomplished. Care is exercised to actually eifect adhesion of the zinc stearate particles to the meshed material granules, without causing fusion of the mass. When the heat "is turned off and the vibration stopped, the tray should be quickly removed to overcome the tendency of accumulated heat to fuse the mass.

All kinds and sizes of grading of suitable emboss ing as well as engraving compounds, customarily used in thermography, etc. may be employed in the improved process to produce improved dull effects, not dependent on heat.

' With some fusible resins, instead of first grading and then treating with zinc stearate, the zinc stearate and resin may be first fused together, the amount of zinc stearate being approximately double that necessary when not en- ,tirely fused together, then ground and graded resulting in an improved embossing compound for producing embossed raised, rounded-out lettering with a dull effect, not dependent upon heat.

This applicationis a continuation in part of my former application Serial Number 101,414 filed September 18, 1936, having the same title as does the present application.

1. A composition in powdered form for use in the production of dull raised printing, said compositioniconsisting of a resin which when melted has a high enough surface tension for use in thermographic printing, and a gloss retarding agent in substantially less amount than the resin, said gloss retarding agent being adapted to float on the resin when melted and provide a roughened and non-reflecting surface by reason of the tendency of the gloss retarding particles not to become wetted by the liquid base, said gloss retarding agent being a metallic soap from the group consisting ofaluminum palmitate and zinc stearate. i

2. A composition in powderedform for use in the production of dull raised printing, said composition consisting of a resin which when melted has a high enough surface tension for use in thermographic printing, and a substance from the group consisting of zinc stearate, and aluminum palmitate. I

3. A composition in powder form for use in the production of dull, raised printing, said composition consisting of a mixture of shellac and zinc stearate.

4. A composition in powder form for use in the production of dull, raised printing, said composition consisting of a mixture of shellac and zinc stearate adhered to particles of shellac, the quantity of zinc stearate being approximately six percent (6%) by weight of the shellac.

5. A composition in powdered form for use in the production of dullraised printing, said com position consisting of a resin which when melted hasahigh enough surface tension for use in thermcgraphic printing, and a gloss retarding agent in substantiallyless amount than the resin, said gloss'retarding agent being adapted to float on the resin when melted and provide a roughened and non-reflecting surface by reason of the tendency, of the gloss'retarding particles not to become Wetted by the liquid resin, the proportion of resin to gloss retarding material being approximately 16 to 1 by weight, the gloss,

retarding agent being zinc stearate.

6. A composition in powdered form for use in the production of dull raised printing, said composition consisting 'of a resin which when melted has a; high enough surface tension for use in 'thermogr aphic printing, and magnesia as a gloss retarding agent. r

' v LIPSI'US. 

